Since a photographic material is composed of a support having an electrically insulating property and photographic layers formed thereon, static charges frequently accumulate on the photographic material due to friction or peeling between the surfaces of the same kind of materials or different kinds of materials during the production of and use of the photographic material. The accumulated static charges cause various problems. For example, in the photographic film prior to development processing, the photographic silver halide emulsions layers are light-exposed by the discharge of the accumulated static charges to form spot-like, branch-like or feather-like stains upon developing the photographic film. These stains are a so-called static marks, which result in a great reduce of, or as the case may be, a complete loss of the quality or the commercial value of the photographic films. For example, it may be easily recognized that if such static marks appear in medical or industrial X-ray photographic films, etc., a misdiagnosis may result. Furthermore, these accumulated static charges cause the attaching of dust, etc., onto the surface of the support film for the photographic material. This results in inducing secondary problemsd such as unevenness in the coating step.
Such static charges are accumulated during the production steps or processing or using steps of the photographic materials as described above. The accumulation of the static charges occurs by the contact friction between the photographic film and a roll during the production step of the photographic film or the separation of the support of the photographic film and the silver halide emulsion layer thereof during the winding or rewinding step of the photographic film. Also, the accumulation of static charges occurs by the separation of the support surface and the emulsion surface of a photographic film in the case of rewinding the finished photographic film in such a high humidity that the photographic films adhere or, for example, the contact and separation between an X-ray photographic film and mechanical parts or an intensifying screen in an automatic photographing machine. The occurrence of the static marks of a photographic material cused by the accumulation of static charges in greater as the sensitivity of the photographic material is increased and the processing speed for the photographic material is increased.
It is considered that the friction electrification (triboelectricity) and the electrification by peeling off are caused by the ionic interaction between the molecules of the materials which are brought into contact but, it is difficult at present to sufficiently estimate structurally and chemically what kind of material is positively charged and what kind of material is negatively charged. However, the accumulation of such static charges is prevented by decreasing the amount of electrification or by increasing the electrical conductivity on the surface of the material to dismiss static charges in a very short period of time before the local discharging by the accumulation of static charges occurs. Thus, various methods of increasing the conductivity of the supports and various coated surface layers of photographic materials have been proposed and the utilizations of various kinds of hygroscopic materials and water-soluble inorganic salts as well as some kinds of surface active agents, polymers, have been attempted. For example, there are known the polymers as described in U.S. Pat. Nos. 2,882,157, 2,972,535, 3,062,785, 3,262,807, 3,514,291, 3,615,531, etc.; the surface active agents as described in British Patent 861,134; U.S. Pat. Nos. 2,982,651, 3,428,456, 3,457,076, 3,454,625, 3,552,972, 3,655,387; and zinc oxide, the semiconductors, colloid silica, as described in U.S. Pat. Nos. 3,062,700, 3,245,833, 3,525,621.
In particular, it is known that among the abovedescribed materials, nonionic surface active agents having one polyoxyethylene chain in one molecule have excellent antistatic properties.
According to the aforesaid techniques, it is possible to considerably restrain the accumulation of static charges by increasing the conductivity of the supports and the coated surface layers of the photographic materials but it is difficult to completely prevent the occurrence of static marks caused by the friction with various kinds of rollers or intesifying screens having different properties form those of the photographic materials.
On the other hand, it is known that the friction electrification and the peeling electrification of the supports and the coated layers of photographic materials can be reduced by using a fluorine-containing compound and the utilization of some kinds of surface active agents, polymers, etc., has been tried. Examples of such materials are the surface active agents as described in Japanese Patent Publication No. 43130/73, Japanese Patent Publication (Unexamined) No. 146248/82, and the polymers as described in Japanese Patent Publication (Unexamined) No. 78834/81. In this case, since the friction, contact, or peeling is a phenomenon relative to the surface of the photographic material, it is considered that the fluorine-containing compound contributing to change the amount of the electrification is the compound existing near the surface of the photographic material.
This is clear from the fact that even when a definite amount of a certain kind of a fluorine-containing surface active agent is incorporated in the coated surface layer of a photographic material, the amount of electrification of the photographic material greatly changes due to the influences of the coating and drying conditions for the photographic material, the nature of various additives used together, and the storing conditions for the photographic material.
Also, in the control of electrification by a fluorine-containing compound, the amount of electrification can be reduced when the material to which the photographic material is brought into contact or from which the photographic material is peeled off, is one kind of material. However, it is difficult to reduce the amount of electrification for each of any plural materials when the photographic material is brought into contact with the plural materials or is peeled off from the plural materials.